#include <iostream>
#include <string>


using namespace std;
string gjd(string a,string b);


int main() {
    int a,b;
    string x="1",y="1",z="0";
    cin >> a >> b;
    for(int i = 2; i <= b-a; i++){
        z = gjd(x,y);
        x = y;
        y = z;
    }
    cout << z;
    return 0;
}

string gjd(string a,string b){
    string r = "";
    int len1 = a.length(),len2 = b.length();
    int d[1000],e[1000],ir[1000];
    for(int i = 0; i < 1000; i++){
        d[i] = 0;
        e[i] = 0;
        ir[i] = 0;
    }
    for(int i = 0; i < len1; i++){
        d[i] = int(a[len1-1-i])-48;
    }
    for(int i = 0; i < len2; i++){
        e[i] = int(b[len2-1-i])-48;
    }
    for(int i = 0; i < max(len1,len2); i++){
        ir[i] = d[i]+e[i];
    }
    for(int i = 0; i < max(len1,len2); i++){
        ir[i+1] += (ir[i])/10;
        ir[i] %= 10;
    }
    int v = 999;
    while(ir[v]==0&&v>=0){
        v--;
    }
    for(int i = v; i>=0; i--){
        r += char(ir[i]+48);
    }
    return r;
}